Benzoxazolon arsonic acids



process described in Patented July 12, 1927.

UNiTE-osTATEs PATENT, OFFICE.

LUDWIG BENDA, 0F MAINKUR, NEAR FRANKFORT-ON-THEMAIN, AND OTTO SIEVERS, OF FECHENHEIM, NEAR FRANKIEoRT o N -TflE M'AIN, GERMANY, ASSIGNORS TO I. G. FARBENINDUSTRIE AKTIENGESEL LSCHAFT, A CORPORATION OF GERMANY.

BENZOXAZOLON ARSONIC ACIDS;

No Drawing. 1 Application filed July 27, 1925, Serial No. 46,500, and in Germany August 11, 1924.

We have found that according to the may be produced by nitrating benzoxazo- 5 tives into the respective arsonic acids by diazotization and treatment with arsenites. The nitro group entering into the para position to the NI-I group When nitrating the benzoxazolones it is not possible to obtain on o l 5-m'tr0ben 20maz0Z0n.-15. L kg. 4-nitro-2 aminophenol are dissolved in 300 liters Water and 10 l. caustic soda solution 38 Be.

the isomeric benzoxazolon-5-ar'sonic acid of- United States Patent the formula:

1,539,? 98 benzoxazolon-G-arsonic acids of the general formula: i

according to the above process.

\Ve have noW' found that the nitrobenzoxazolones (IV) obtained by the action of phosgen on 1-hydroxy-2eaminol-nitrobenzol and itsderivatives (III) can by reduction (V) subsequent diazotizing and treatment with arsentites (VI) be converted into compounds of formula II'and that'surprisingly the benzoxazolon-ring remains intact during all these operations. Forinstance:

v w U a. as,

Phosgene is then passed in While cooling, allowing atthe .saine timefurther 10 l. caustic soda solution to flow in gradually. After the liquid has become strongly acid, the 5-ni-trobenzoxazolon is decanted by suction. The final stage of the reaction may be ascertained by a diazotizing test. The new compound may be reduced Without refining. It is sparingly soluble in Water, dissolves in glacial acetic acid, acetone, alcohol and ether, and forms With alkalies in Water easily soluble, and with an excess of alkalies sparingly soluble'yellow salts of alkalies. Melting point 228229 C.

5-aminobenzomaz0lon.9 kg. 5-nitrobenzoxazolon are gradually and in small portions added to a boiling hot suspension of 11 kg. iron filings in 40 liters Water and 1.5 liters acetic acid 50%. After reduction is complete it is brought up to 80 1. made alkaline, boiling hot, with 2.5 kg. sodium carbonate solution and decanted by suction.

On cooling the amino benzoXazolon crystalthe solution which may easily be prepared and, on allowing to stand assumes a deep color. The diazo solution coupled with re' sorcinol is yellow-red and with R-salt redviolet.

Bcneowaeolon 5 arsom'c acid. 8.5 kg. 5-aminobenzoxazolon are dissolved in 20 liters water and 2 liters caustic soda solution 38 B., 2.6 liters nitrite solution (of which.

130 00.:1000 nitrite) and 28 kg. ice added and finally diazotized with 6 liters hydrochloric acid. 7

I The diazo solution is gradually added to a solution of 15 of 6.4 kg. sodium arsenite and 9 kg. sodium carbonate in 40 liters water. When all has been added and the liquid does not any longer contain a diazo compound it is acidulated and rapidly decanted by suction. After standing for some length of time and cooling the arsonic acid is precipitated from the filtrate in the shape of yellowbrown crusts which may be recrystallized from a hot sodium acetate solution or boiling water then ,forming colorless crystals. In alkalies they dissolve easily cold. In the customary organic solvents they dissolvesparingly or are insoluble.

Example 2.

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SOaHz '7-methyZ-5mitr0bene0maz0Z0n.-The -nitro-3-amino-2-hydroxy-l-methylbenzol obtained by the reduction of dinitrocresol with sodium disulfide is dissolved in 500 liters water and 80 liters caustic soda solution 10" B. and phosgene added. liters caustic soda solution are added until the nitroaminocresol is used up, and the solution is then decanted by suction. The nitromethylbenzoxazolon thus obtained may easily be reduced. It dissolves in glacial acetic acid, alcohol, acetone and ether, is sparingly soluble in hot Water, but dissolves readily in dilute alkalies forming alkali metal salts in the form of crystalline yellow needles. The melting point is 236237 C.

7 methyl 5 amnobenzomaeolon. 9 kg. 7-methyl-5-nitrobenzoxazolon are gradually added to a boiling suspension of 11 kg. iron filings in 410 liters water and 1.5 liters acetic acid After complete reaction it is made up to liters rendered alkaline while boiling hot with 2.5 kg. sodium carbonate quickly takes on a dark color.

"Amal a Z?)enzozcazolonfl-arsoaic acid. 3.8 kg. l-methyl-G-ammobenzoxazolon are mixed with 1- liters water and 12 kg. ice, adding-.4

liters hydrochloric acid 38%, this is then diaaotized with2.6 liters nitrite solution (130 cc.:1000 NN). To the diazo' solution 6.4 kg. sodium arsenite are added While stirring Well, which is then rendered slightly alkaline by adding With care about 5 kg. sodium carbonate solution. The solutionis stirred until a diazo compound cannot be found any longer. It is then acidulated and immediately decanted by suction. After standing rcr some length of time the arsonic acid is precipitated as brown crusts which may be refined from sodium acetate solution or their sodium salt, then forming colorless crystals readily soluble in alkalies and sparingly so in cold Water. In the customary organic solvents the 7-methylbenzoxazolon-5arsonic acid is insoluble.

7 Example 3.

. v o c=o 7V ol-m ix n 7-0hZ07'0-5-nit7'0benzomazolom-The 5-nitro-3-amino-2-hydroxyl-chlorobenzene ob tained by the reduction of 132 kg. dinitrochlorophenol with sodium disulphide is dissolved in 500 liters of water and 80 liters of caustic soda solution 10 B. Phosgene is passed into the blood-red solution gradually adding 40 liters caustic soda solution until the chloronitroaminophenol is'used up. The precipitated chloronitrobenzoxazolon is decanted by suction and may be reduced imme diately.

It dissolves in acetic acid, acetone, ether, and alcohol, sparingly so in hot water, benzene, but readilyin dilute alkalies, forming alkali metal salt-s as yellowish crystalline needles. Melting point 210211 C.

7-0hZ0r0-5-aminobencowacolon.9 kg. 7- chloro-5-nitrobenzoXaz0lon are gradually entered into a boiling suspension of 11 kg. iron filings in 10 liters Water and 1.5 litersacetic acid 50%. After complete reduction the solution is made up to 80 liters rendered alkaline While boiling hot with 2.5 kg. sodium carbonate solution and decanted by suction. The aminomethylbenzoxazolon crystallizes on cooling in the form of faintly colored needles. It dissolves in hot water, alcohol and acetone, is however practically insoluble in ether and benzene. It dissolves readily in dilute acids and in alkalies. Its alkaline solution rapidly becomes dark colored. Its diazo solution coupled with R-salt is bluishred and with resorcinol orange.

7- chlo r'obenzox-crzoloaare om'c awz'al.4. 3 kg. 7-chloro-5-aminobenzoxazolon are mixed with 4: liters water and 4 liters hydrochloric acid 38% and 12 kg. ice added. The solution is diazotized by the addition of 2.6 liters nitrite solution. (130 00.:1000 NN). 6.4: kg. sodium arsen'ite are added while stirring well and the solution is rendered slightly alkaline by adding with care about 5 kg. sodium carbonate solution. This is stirred until a diazo compound cannot be demonstrated any longer. It is then acidulated and decanted by suction. After standing for some length of time the arsonic acid is precipitated as brown crusts. It may be purified over its sodium salt and then forms white crystals easily soluble in alkalies, sparingly so in hot water and insoluble in cold water. In the customary organic solvents the 7 -chloro-beu- ZoXazolon-5-arsonic acid is insoluble.

Having now particularly described and ascertained the nature of our said invention and in What manner the same is to be performed, we declare, that what we claim is:

1. Process for the production of benzoxazolon-5-arsonic acids'by allowing phosgene to act on aryl-l-hydroxy-Qaminoi-nitrocompounds, by reducing the 5-nit-roaryloxa- Zolons, thus formed, and transforming these amino compounds into the corresponding arsonic acids in the customary manner.

- 2. As' new product the 'T-chlorobenz'oxazolon-o-arsonic acid of the formula:

LUDWVIG BENDA. OTTO SIEVERS. 

